Can existing table with Data, defined as SET be changed to MULTISET Table without dropping and re-creating the table?
I think you mean to say thus(example):
Create multiset table dbname.multiset_table_name as dbname.set_tbl with data;
It works. Why dont you try??
You can create a copy of a table and change the table level attribute from SET to MULTISET. This can be done with the statement for cloning tables CREATE TABLE AS...
You can't change just the attribute from SET to MULTISET.